mmc: fix response timeout after switch command

After issuing the switch command: Wait until 'current state' of the card
status becomes 'tran'. This prevents from response timeout at the next
command because of 'current state' = 'data'.

Signed-off-by: Stefan Bosch <stefan_b@posteo.net>
Reviewed-by: Jaehoon Chung <jh80.chung@samsung.com>